An information processing system having multiple memory devices has been known. One kind of such an information processing system disclosed in Patent Document 1 generates N (an integer of two or more) pieces of distributed data from secret data in accordance with the secret sharing scheme, and then stores the N pieces of generated distributed data each into one of N memory devices.
In the above information processing system, even if a user intends to unscrupulously obtain the secret data, for example, the secret data is not successfully restored unless the user obtains k (an integer of two or more and less than N) pieces of distributed data among N pieces of distributed data generated from the secret data. Furthermore, the above information processing system changes the memory devices of the storing destinations to store the N pieces of distributed data in accordance with a predetermined scheme each time when secret data is to be stored.